tesseract::LLSQ Class Reference

#include <linlsq.h>

Public Member Functions
	LLSQ ()
void	clear ()
void	add (double x, double y)
void	add (double x, double y, double weight)
void	add (const LLSQ &other)
void	remove (double x, double y)
int32_t	count () const
double	m () const
double	c (double m) const
double	rms (double m, double c) const
double	pearson () const
FCOORD	mean_point () const
double	rms_orth (const FCOORD &dir) const
FCOORD	vector_fit () const
double	covariance () const
double	x_variance () const
double	y_variance () const

Detailed Description

Definition at line 29 of file linlsq.h.

Constructor & Destructor Documentation

LLSQ()

tesseract::LLSQ::LLSQ ( )

inline

Definition at line 31 of file linlsq.h.

         {   // constructor
    clear(); // set to zeros
  }

Member Function Documentation

add() [1/3]

void tesseract::LLSQ::add

(

const LLSQ &

other

)

Definition at line 67 of file linlsq.cpp.

                                {
  total_weight += other.total_weight;
  sigx += other.sigx; // update accumulators
  sigy += other.sigy;
  sigxx += other.sigxx;
  sigxy += other.sigxy;
  sigyy += other.sigyy;
}

add() [2/3]

void tesseract::LLSQ::add	(	double	x,
		double	y
	)

Definition at line 49 of file linlsq.cpp.

                                 { // add an element
  total_weight++;                    // count elements
  sigx += x;                         // update accumulators
  sigy += y;
  sigxx += x * x;
  sigxy += x * y;
  sigyy += y * y;
}

add() [3/3]

void tesseract::LLSQ::add	(	double	x,
		double	y,
		double	weight
	)

Definition at line 58 of file linlsq.cpp.

                                                {
  total_weight += weight;
  sigx += x * weight; // update accumulators
  sigy += y * weight;
  sigxx += x * x * weight;
  sigxy += x * y * weight;
  sigyy += y * y * weight;
}

c()

double tesseract::LLSQ::c

(

double

m

)

const

Definition at line 116 of file linlsq.cpp.

                             { // get constant
  if (total_weight > 0.0) {
    return (sigy - m * sigx) / total_weight;
  } else {
    return 0; // too little
  }
}

clear()

void tesseract::LLSQ::clear

(

)

Definition at line 34 of file linlsq.cpp.

                 {  // initialize
  total_weight = 0.0; // no elements
  sigx = 0.0;         // update accumulators
  sigy = 0.0;
  sigxx = 0.0;
  sigxy = 0.0;
  sigyy = 0.0;
}

count()

int32_t tesseract::LLSQ::count ( ) const

inline

Definition at line 44 of file linlsq.h.

                        { // no of elements
    return static_cast<int>(total_weight + 0.5);
  }

covariance()

double tesseract::LLSQ::covariance ( ) const

inline

Definition at line 76 of file linlsq.h.

                            {
    if (total_weight > 0.0) {
      return (sigxy - sigx * sigy / total_weight) / total_weight;
    } else {
      return 0.0;
    }
  }

m()

double tesseract::LLSQ::m

(

)

const

Definition at line 100 of file linlsq.cpp.

                     { // get gradient
  double covar = covariance();
  double x_var = x_variance();
  if (x_var != 0.0) {
    return covar / x_var;
  } else {
    return 0.0; // too little
  }
}

mean_point()

FCOORD tesseract::LLSQ::mean_point

(

)

const

Definition at line 166 of file linlsq.cpp.

                              {
  if (total_weight > 0.0) {
    return FCOORD(sigx / total_weight, sigy / total_weight);
  } else {
    return FCOORD(0.0f, 0.0f);
  }
}

pearson()

double tesseract::LLSQ::pearson

(

)

const

Definition at line 152 of file linlsq.cpp.

                           { // get correlation
  double r = 0.0;              // Correlation is 0 if insufficient data.
 
  double covar = covariance();
  if (covar != 0.0) {
    double var_product = x_variance() * y_variance();
    if (var_product > 0.0) {
      r = covar / std::sqrt(var_product);
    }
  }
  return r;
}

remove()

void tesseract::LLSQ::remove	(	double	x,
		double	y
	)

Definition at line 82 of file linlsq.cpp.

                                    { // delete an element
  if (total_weight <= 0.0) {            // illegal
    EMPTY_LLSQ.error("LLSQ::remove", ABORT);
  }
  total_weight--; // count elements
  sigx -= x;      // update accumulators
  sigy -= y;
  sigxx -= x * x;
  sigxy -= x * y;
  sigyy -= y * y;
}

rms()

double tesseract::LLSQ::rms	(	double	m,
		double	c
	)		const

Definition at line 130 of file linlsq.cpp.

                                         { // get error
  double error;                              // total error
 
  if (total_weight > 0) {
    error = sigyy + m * (m * sigxx + 2 * (c * sigx - sigxy)) + c * (total_weight * c - 2 * sigy);
    if (error >= 0) {
      error = std::sqrt(error / total_weight); // sqrt of mean
    } else {
      error = 0;
    }
  } else {
    error = 0; // too little
  }
  return error;
}

rms_orth()

double tesseract::LLSQ::rms_orth

(

const FCOORD &

dir

)

const

Definition at line 195 of file linlsq.cpp.

                                             {
  FCOORD v = !dir;
  v.normalise();
  return std::sqrt(x_variance() * v.x() * v.x() + 2 * covariance() * v.x() * v.y() +
                   y_variance() * v.y() * v.y());
}

vector_fit()

FCOORD tesseract::LLSQ::vector_fit

(

)

const

Definition at line 250 of file linlsq.cpp.

                              {
  double x_var = x_variance();
  double y_var = y_variance();
  double covar = covariance();
  double theta = 0.5 * atan2(2.0 * covar, x_var - y_var);
  FCOORD result(cos(theta), sin(theta));
  return result;
}

x_variance()

double tesseract::LLSQ::x_variance ( ) const

inline

Definition at line 83 of file linlsq.h.

                            {
    if (total_weight > 0.0) {
      return (sigxx - sigx * sigx / total_weight) / total_weight;
    } else {
      return 0.0;
    }
  }

y_variance()

double tesseract::LLSQ::y_variance ( ) const

inline

Definition at line 90 of file linlsq.h.

                            {
    if (total_weight > 0.0) {
      return (sigyy - sigy * sigy / total_weight) / total_weight;
    } else {
      return 0.0;
    }
  }

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The documentation for this class was generated from the following files:

• /media/home/debian/src/github/tesseract-ocr/tesseract/src/ccstruct/linlsq.h
• /media/home/debian/src/github/tesseract-ocr/tesseract/src/ccstruct/linlsq.cpp